SKA3-mediated hypoxia tolerance and metabolic reprogramming promote liver metastasis in lung adenocarcinoma.

Late-stage lung adenocarcinoma (LUAD) frequently results in distant metastasis, with liver metastasis indicating the poorest prognosis. To successfully colonize the liver, metastatic LUAD cells must overcome its relatively hypoxic microenvironment. This study explores the metabolic adaptations that facilitate LUAD liver metastasis, identifying Spindle and Kinetochore Associated Protein 3 (SKA3) as a critical mediator. Under hypoxic conditions, SKA3 expression is significantly upregulated, driving glucose metabolic reprogramming in LUAD cells to enable survival within the liver's hypoxic niche. Mechanistically, SKA3 competitively binds to prolyl hydroxylase domain-containing protein 2 (PHD2), disrupting its interaction with hypoxia-inducible factor 1-alpha (HIF-1α). Consequently, stabilized HIF-1α further enhances glycolytic enzyme transcription, amplifying glycolysis and enabling adaptation to liver hypoxia. Furthermore, hypoxia upregulates the E3 ubiquitin ligase MDM2, promoting p53 ubiquitination and degradation, thereby relieving p53-mediated repression of SKA3 and further reinforcing the SKA3/HIF-1α axis. Interestingly, HIF-1α directly binds to the hypoxia response element (HRE) in the SKA3 promoter, creating a positive feedback loop to maintain high SKA3 expression. Thus, SKA3-mediated metabolic reprogramming significantly contributes to LUAD cells colonization and proliferation in the liver. Finally, our findings demonstrated that the SKA3/HIF-1α axis was critical for establishing hypoxia tolerance in LUAD cells, underscoring its potential as a therapeutic target for treating liver metastasis in LUAD.